Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quem são todos os candidatos quando Sam Rayburn era titular?
 ###Tabelas: CREATE TABLE florida_counties_ranked_by_per_capita_income (florida_counties_ranked_by_per_capita_income_id AUTO_INCREMENT PRIMARY KEY, County VARCHAR, Per capita income VARCHAR, Median household income VARCHAR, Median family income VARCHAR, Population INT, Number of households INT) CREATE TABLE tournament_for_the_championship_of_canada (tournament_for_the_championship_of_canada_id AUTO_INCREMENT PRIMARY KEY, Players VARCHAR, Games Won INT, Games Lost INT, Total points INT, Grand Average VARCHAR, Best Winning Average VARCHAR, Best Run INT) CREATE TABLE  (_id AUTO_INCREMENT PRIMARY KEY, District VARCHAR, Incumbent VARCHAR, Party VARCHAR, First elected INT, Result VARCHAR, Candidates VARCHAR) CREATE TABLE notable_works (notable_works_id AUTO_INCREMENT PRIMARY KEY, Year INT, Play VARCHAR, Author VARCHAR, Theatre VARCHAR, Type VARCHAR, Role VARCHAR) CREATE TABLE negotiation_progress (negotiation_progress_id AUTO_INCREMENT PRIMARY KEY, Screening Started VARCHAR, Screening Completed VARCHAR, Chapter Unfrozen VARCHAR, Chapter Opened VARCHAR, Chapter Closed VARCHAR)  
SELECT Candidates FROM  WHERE Incumbent = Sam Rayburn